1.2: What is a ISO?
- Page ID
- 151073
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The meaning of ISO (International Standard Organization) is how sensitive the image sensor is to the amount of light present. The sensitivity is reacting speed by light. If the value of ISO is high, you can take a picture without a flash even if the amount of light is low. However, a noise will occur on a photo if using a high ISO setting because higher gain, more noise. You can see the difference in the value of ISO using same shutter speed and aperture in following pictures.
• Low speed: ISO 25~50
• Middle speed: ISO 100~200
• High speed: ISO 400~
As a beginner, use the minimum possible ISO setting. You should increase the ISO setting only when the shutter speed is too slow to hand hold, you need a faster shutter speed to capture action, or you need a smaller aperture for depth of field. For example, suppose you are in a concert and can not use a flash. Your digital camera will automatically select good combination of the shutter speed and exposure setting. However, if you find the camera is using a shutter speed that is too slow (1/60 sec. and slower) to handhold the camera steady and shake-free (thus resulting in blurred pictures), and you cannot open up the aperture anymore, and you do not have a tripod or other means to hold the camera steady, you might select higher ISO setting which will then allow you to select a faster shutter speed
Usually the ISO setting of regular digital cameras is equivalent to 100 or Auto. If you
want to change the ISO setting, you should check whether you can change it or not in
the manual.